MEASUREMENT OF DISSOLVED OXYGEN CONCENTRATION FOR OXYGEN ACTIVATED SLUDGE METHOD

摘要

PURPOSE:To find the average quantity of dissolved oxygen from the flow rate of an injection gas containing oxygen and an exhaust gas, oxygen partial pressures of the gases and the temperature of water in an aeration tank by deriving a fixed relation ship between dissolved oxygen and the flow rate and oxygen partial pressure of the gas containing oxygen. CONSTITUTION:The point of this method is that closed type multistage oxygen aeration plants are designed to make dissolved oxygen almost equal among tanks. Assuming that dissolved oxygen are almost equal among tanks, the amount of dissolved oxygen in any tank can be replaced with average amount of the dissolved oxygen among all tanks, which simplifies the formula. In the treatment system as illustrated, the flow rate Fe of an injection gas (a) containing oxygen is measured with a meter 2 and the flow rate Fa of an exhaust gas (d) from an aeration tank 1 with a meter 3. Partial pressure Pe, P1, P2 and Pa are measured at sampling points of an injection gas conduit, tanks 1A and 1B and an exhaust conduit and the water temperature T in the tanks with a temperature sensor 7 to determine the average amount of dissolved among the tanks with an integrator 8.